Crontab scheduling

I'm trying to create a schedule for our Windows updates in the K1000 that will run the 1st & 3rd week of every month. I'm having a hard time figuring this out with crontab. Anyone have any ideas? I'm also open to having it run every other week.

Answers

I use 00 1 15-21 * * for week 3 patch jobs and then use my power management software to wake the machines only on the night I want them to patch. The 15-21 encompasses the third week of the month and I control the day by waking the machines as detailed above.

I do not believe the kace (OpenBSD) can support expressions in the cron commands. If it does:
https://www.google.com/search?q=crontab+to+run+every+other+week&rls=com.microsoft:en-US&ie=UTF-8&oe=UTF-8&startIndex=&startPage=1